From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH] usb: dwc3: omap: Fix imprecise external abort and oops on boot Date: Thu, 8 Dec 2016 14:57:25 -0800 Message-ID: <20161208225724.GI4920@atomide.com> References: <20161208032108.21962-1-tony@atomide.com> <87lgvqkb6f.fsf@linux.intel.com> <20161208153734.GF4264@atomide.com> <9cce1e34-2fec-9477-4827-6b4c67920a8a@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <9cce1e34-2fec-9477-4827-6b4c67920a8a-l0cyMroinI0@public.gmane.org> Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Grygorii Strashko Cc: Felipe Balbi , Greg Kroah-Hartman , Roger Quadros , Sekhar Nori , linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-omap@vger.kernel.org * Grygorii Strashko [161208 13:54]: > Hi Tony, > > On 12/08/2016 09:37 AM, Tony Lindgren wrote: > > * Felipe Balbi [161208 01:45]: > >> Tony Lindgren writes: > >>> Somehow starting with v4.9-rc7 there have been imprecise > >> > >> There's nothing touching dwc3 since v4.9-rc5. > > > > Right, nothing obvious has changed. I think it's just a slight timing > > change in the code that started triggering it. > > > >>> external aborts on omap5-uevm dwc3 controller. I have not been > >>> able to bisect what exactly triggered this as it does not always > >>> happen. It seems that something changed with probing that > >>> now exposes the issue: > >>> > >>> Unhandled fault: imprecise external abort (0x1406) at 0x00000000 > >> > >> hmmm, clock disabled... dwc3-omap shouldn't have pm runtime at all. > > > > It does for the interconnect target module clkctrl register via PM > > runtime. That's the "usb_otg_ss" module. > > > >>> ... > >>> PC is at dwc3_omap_interrupt_thread+0x20/0x80 > >>> LR is at irq_thread_fn+0x1c/0x54 > >>> ... > >>> [] (dwc3_omap_interrupt_thread) from [] > >>> (irq_thread_fn+0x1c/0x54) > >>> [] (irq_thread_fn) from [] (irq_thread+0x12c/0x1f0) > >>> [] (irq_thread) from [] (kthread+0xdc/0xf4) > >>> [] (kthread) from [] (ret_from_fork+0x14/0x3c) > >>> ... > >>> > >>> Unable to handle kernel paging request at virtual address ffffffec > >>> ... > >>> Internal error: Oops: 37 [#2] SMP ARM > >>> PC is at kthread_data+0x4/0xc > >>> LR is at irq_thread_dtor+0x28/0xd0 > >>> ... > >>> [] (kthread_data) from [] (irq_thread_dtor+0x28/0xd0) > >>> [] (irq_thread_dtor) from [] (task_work_run+0xb8/0xdc) > >>> [] (task_work_run) from [] (do_exit+0x314/0xa20) > >>> [] (do_exit) from [] (die+0x410/0x474) > >>> [] (die) from [] (do_DataAbort+0xb4/0xb8) > >>> [] (do_DataAbort) from [] (__dabt_svc+0x58/0x80) > >>> Exception stack(0xee777ec8 to 0xee777f10) > >>> 7ec0: 0000014d ee6e6f10 00000034 fc020034 ee6e6f10 ee1eec00 > >>> 7ee0: 00000000 00000000 ee6ec640 c038a4bc 00000000 00000000 00000000 ee777f18 > >>> 7f00: c038a4d8 c0989fa8 60000013 ffffffff > >>> [] (__dabt_svc) from [] (dwc3_omap_interrupt_thread+0x20/0x80) > >>> [] (dwc3_omap_interrupt_thread) from [] (irq_thread_fn+0x1c/0x54) > >>> [] (irq_thread_fn) from [] (irq_thread+0x12c/0x1f0) > >>> [] (irq_thread) from [] (kthread+0xdc/0xf4) > >>> [] (kthread) from [] (ret_from_fork+0x14/0x3c) > >>> > >>> Fix the issue by making sure the dwc3 interrupts are disabled > >>> before we call devm_request_threaded_irq(). > >> > >> that should already be the case. Are you sure that register isn't zero > >> in probe? > > > > Looks like irq0_status = 0 and irqmisc_status = 0x2121. Also just > > clearing irqmisc with dwc3_omap_write_irqmisc_clr(omap, 0xffffffff) > > stops the issue from happening. > > > > There is some deferred probing happening but irqmisc is always 0x2121. > > > > My assumption is that you have race here between IRQ handler and PM runtime > in error handling path during deferred probing. > > Will below change fix issue for you? I think you figured out why it behaves that way :) Seems to work based on few boot tests. Probably both should be applied, my original patch to prevent spurious interrupts before things are initialized, this to disable interrupts before pm_runtime_suspend() on exit path: Tested-by: Tony Lindgren > diff --git a/drivers/usb/dwc3/dwc3-omap.c b/drivers/usb/dwc3/dwc3-omap.c > index 29e80cc..dbc21bc 100644 > --- a/drivers/usb/dwc3/dwc3-omap.c > +++ b/drivers/usb/dwc3/dwc3-omap.c > @@ -517,12 +517,12 @@ static int dwc3_omap_probe(struct platform_device *pdev) > if (ret) { > dev_err(dev, "failed to request IRQ #%d --> %d\n", > omap->irq, ret); > - goto err1; > + goto err11; > } > > ret = dwc3_omap_extcon_register(omap); > if (ret < 0) > - goto err1; > + goto err11; > > ret = of_platform_populate(node, NULL, NULL, dev); > if (ret) { > @@ -538,6 +538,8 @@ static int dwc3_omap_probe(struct platform_device *pdev) > extcon_unregister_notifier(omap->edev, EXTCON_USB, &omap->vbus_nb); > extcon_unregister_notifier(omap->edev, EXTCON_USB_HOST, &omap->id_nb); > > +err11: > + disable_irq(omap->irq); > err1: > pm_runtime_put_sync(dev); > pm_runtime_disable(dev); > > > -- > regards, > -grygorii -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html